Backlight apparatus, and a liquid crystal display (LCD) therewith

ABSTRACT

Dissipation of heat generated by a luminescent source, such as a fluorescent lamp, of a backlight apparatus and an LCD therewith is enhanced by providing a proximity section in a holder, making the hottest part the closest to the holder for efficient heat conduction.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention generally relates to a backlight apparatus,and a liquid crystal display (LCD), and especially relates to abacklight apparatus including a luminescent source that generates heat,such as a fluorescent lamp, and an LCD that employs the backlightapparatus.

[0003] Conventionally, CRT (cathode-ray tube) displays have been used.In recent years, use of thin displays that employ an LCD panel has beenprogressing. Display quality of the LCD has been enhanced, andenlargement and higher brightness of the displays are desired fortelevision use, etc. With requirements of brighter LCDs increasing,demands are increasing for a backlight apparatus that can provide theillumination for the enlarged and brighter liquid crystal panel.

[0004] 2. Description of the Related Art

[0005] Conventional LCDs have been used mainly by notebook PCs, when upto about 13 inch displays are the main thrust with a screen brightnessof around 150 cd/m2 and a resolution of XGA. FIG. 1 and FIG. 2 show anLCD 1A that is an example of a conventional LCD.

[0006] The LCD 1A is configured with a liquid crystal panel 2A, ahousing 5, a backlight apparatus 10A, etc. The housing 5 holds theliquid crystal panel 2A and the backlight apparatus 10A through a resinframe 6 and a backboard 9. Here, the backlight apparatus 10A givespredetermined brightness to a display of the liquid crystal panel 2A byilluminating the liquid crystal panel 2A from the back.

[0007] The backlight apparatus 10A generally includes a fluorescentlight bulb 3 serving as a light source, a light guide board 4 thatguides the light from the fluorescent light bulb 3 to the liquid crystalpanel 2A, and a holder 7 that reflects the light from the fluorescentlight bulb 3 to the light guide board 4, while supporting thefluorescent light bulb 3 via a rubber holder.

[0008] In the fluorescent light bulb 3, mercury is enclosed in Ar gas orNe gas, and, on the wall of the fluorescent light bulb 3, a fluorescentmaterial is applied. Mercury gas generates ultraviolet rays duringelectric discharge, and light is generated when the ultraviolet rays hitthe fluorescent material.

[0009] The light guide board 4, made from acrylic resin, collaborateswith an optical sheet 8 installed, and transmits the light from thefluorescent light bulb 3 and distributes the light all over the liquidcrystal panel 2A. In the case of the LCD 1A that provides a relativelysmall screen size (about 13 inches), where no particularly highresolution and no particularly high screen brightness are required, thebacklight apparatus 10A is provided only on one side of the light guideboard 4, and only one fluorescent light bulb 3 is provided.

[0010] A larger screen size, 14 to 15 inches, has been used for themonitor of a desktop PC. FIGS. 3 and 4 show an LCD 1B that provides arelatively large screen size, for which resolution of SXGA and screenbrightness of about 250 cd/m are required. For this reason, twobacklight apparatuses 10B are installed in the LCD 1B, such that one ofthe backlight apparatuses is provided on each side of the light guideboard 4. Further, each backlight apparatus 10B includes two fluorescentlight bulbs 3. However, with infusion of DVD drives, users require thatPC monitors provide even larger screens and higher brightness for movieviewing and so on.

[0011] In order to increase the screen size and brightness, there is aproblem to solve. That is, the fluorescent light bulb 3 provided in thebacklight apparatus 10B generates heat with luminescence. Especially inboth ends of the fluorescent light bulb 3 where electrodes areinstalled, temperature can rise higher than 120 degrees C., when a largeelectric current is provided in order to obtain a high brightness. Forthis reason, some conventional solutions provide a rubber holder made ofa heat-conductive material at both ends of the fluorescent light bulb 3,such that heat can be dissipated to the holder 7.

[0012] Nevertheless, the heat generated by the fluorescent light bulb 3cannot be sufficiently dissipated by the holder 7 via the rubber holder,causing lowering of the brightness of the fluorescent light bulb 3, andbreaking of a solder joint that connects the electrode section andwiring. Another solution has been to provide a larger holder 7 for moreefficient heat-dissipation, however, it causes dimensions of the LCDs 1Aand 1B to become large.

[0013] The present invention is made in view of the above-mentionedpoint, and it aims at offering a backlight apparatus that canefficiently dissipate the heat generated in the luminescent source, andan LCD that employs the backlight apparatus.

SUMMARY OF THE INVENTION

[0014] It is a general object of the present invention to provide abacklight apparatus for a liquid crystal display (LCD), and a liquidcrystal display therewith that substantially obviate one or more of theproblems caused by the limitations and disadvantages of the related art.

[0015] Features and advantages of the present invention will be setforth in the description that follows, and in part will become apparentfrom the description and the accompanying drawings, or may be learned bypractice of the invention according to the teachings provided in thedescription. Objects as well as other features and advantages of thepresent invention will be realized and attained by the backlightapparatus for the LCD, and the LCD therewith particularly pointed out inthe specification in such full, clear, concise, and exact terms as toenable a person having ordinary skill in the art to practice theinvention.

[0016] To achieve these and other advantages and in accordance with thepurpose of the invention, as embodied and broadly described-herein, theinvention provides, among other means, a proximity section in a holderthat holds the luminescent sources, which helps improve heatconductivity for a center part where the luminescent sources are closetogether, and the temperature is the highest. The proximity section thatis close to the luminescent sources has a space on its back side that isused to lay wiring, resulting in space saving. Where there are three ormore luminescent sources, one or two centrally positioned luminescentsources that tend to be the hottest are placed closer to the holder thanother luminescent sources, such that heat-dissipation of the centrallypositioned luminescent sources is enhanced, resulting in an improvementof overall heat dissipation efficiency. Since the temperature of twoelectrode sections toward the ends of each of the luminescent sourcestends to be the highest, the distance between the luminescent source andthe holder in the longitudinal direction of the luminescent source ismade such that the distance is the smallest at the two ends, and thelargest at the center. This improves uniformity in brightness of theluminescent source. A supporting component is provided with a projectingsection such that the projecting section is thermally connected to ahousing such that the heat is dissipated effectively. The housing canprovide a concavity to contain the projecting section such that thethermally connecting area is increased, resulting in a higher efficiencyof the heat-dissipation. A heat-dissipating component can be providedbetween the supporting component and a light guide board such that theheat dissipation is further improved. The supporting component can bemade of an insulating material such that a high electric current flowinginto the luminescent source is not discharged externally. Providing aprojecting section to the insulating material further suppressesundesired electric discharge.

[0017] The LCD of the present invention employs the backlight apparatusof the present invention, resulting in a reliable product that deliverssatisfactory image display at a high brightness, due to the highefficiency of the heat-dissipation.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018]FIG. 1 is a figure for explaining an LCD having a small screensize, which is provided with a conventional backlight apparatus;

[0019]FIG. 2 shows an expanded view of a portion indicated by an arrowA1 in FIG. 1;

[0020]FIG. 3 is a figure for explaining an LCD having a large screensize, which is provided with a conventional backlight apparatus;

[0021]FIG. 4 shows an expanded view of a portion indicated by an arrowA2 in FIG. 3;

[0022]FIG. 5 is a perspective diagram showing an LCD and backlightapparatus of a first embodiment of the present invention;

[0023]FIG. 6 is a sectional drawing showing a main part of the LCD andbacklight apparatus of the first embodiment of the present invention;

[0024]FIG. 7 is a sectional drawing showing a main part of the LCD andbacklight apparatus of a second embodiment of the present invention;

[0025]FIG. 8 is a sectional drawing showing a main part of the LCD andbacklight apparatus of the third embodiment of the present invention;

[0026]FIG. 9 is a plan showing the LCD and backlight apparatus of thefourth embodiment of the present invention;

[0027]FIG. 10 is an exploded and perspective diagram showing the LCD ofthe fifth embodiment of the present invention;

[0028]FIG. 11 is an exploded and perspective diagram showing thebacklight apparatus of the fifth embodiment of the present invention;

[0029]FIG. 12 is a perspective diagram showing an expanded view of amain part of the backlight apparatus of the fifth embodiment of thepresent invention (No. 1);

[0030]FIG. 13 is a perspective diagram showing an expanded view of themain part of the backlight apparatus of the fifth embodiment of thepresent invention (No. 2);

[0031]FIG. 14 is a perspective diagram showing an expanded view of themain part of the backlight apparatus of the fifth embodiment of thepresent invention (No. 3);

[0032]FIG. 15 is an exploded and perspective diagram showing a main partof a fluorescent light bulb assembly prepared in the LCD and backlightapparatus of the sixth embodiment of the present invention;

[0033]FIG. 16 is a perspective diagram showing a main part of thefluorescent light bulb assembly prepared in the LCD and backlightapparatus of the sixth embodiment of the present invention;

[0034]FIG. 17 is a sectional drawing showing a principal part of thefluorescent light bulb assembly prepared in the LCD and backlightapparatus of the sixth embodiment of the present invention;

[0035]FIG. 18 is an exploded and perspective diagram showing a main partof the fluorescent light bulb assembly prepared in the LCD and backlightapparatus of the seventh embodiment of the present invention;

[0036]FIG. 19 is a sectional drawing showing a main part of thefluorescent light bulb assembly prepared in the LCD and backlightapparatus of the seventh embodiment of the present invention;

[0037]FIG. 20 is a perspective diagram showing a main part of thefluorescent light bulb assembly prepared in the LCD and backlightapparatus of the eighth embodiment of the present invention;

[0038]FIG. 21 is a front view showing a main part of the fluorescentlight bulb assembly prepared in the LCD and backlight apparatus of theeighth embodiment of the present invention;

[0039]FIG. 22 is a sectional drawing showing a main part of thefluorescent light bulb assembly prepared in the LCD and backlightapparatus of the eighth embodiment of the present invention; and

[0040]FIG. 23 shows an expanded view near an insulation projection.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] In the following, embodiments of the present invention will bedescribed with reference to the accompanying drawings.

[0042] A first embodiment will be described referring to FIG. 5 and FIG.6 that show a backlight apparatus 20A, and an LCD 21A using thebacklight apparatus 20A of the first embodiment of the presentinvention. The LCD 21A includes a liquid crystal panel 22, a housing 25,etc. in addition to the backlight apparatus 20A. The housing 25 has aresin frame 26 inside, which holds the liquid crystal panel 22. Further,a backboard 29 is provided at a lower part of the resin frame 26, andthe backlight apparatus 20A is arranged between the backboard 29 and thehousing 25.

[0043] The backlight apparatus 20A gives predetermined brightness to thedisplay of the liquid crystal panel 22 by illuminating the liquidcrystal panel 22 from the back. The backlight apparatus 20A includes alight guide board 24 and a fluorescent light bulb assembly 40A. Further,the fluorescent light bulb assembly 40A includes a fluorescent lightbulb 23, a holder 27, a rubber holder 32, and wiring 33. In addition,the fluorescent light bulb assembly 40A is arranged such that it can bedetached from and attached to the main part of the backlight apparatus20A in order to facilitate maintenance service.

[0044] The fluorescent light bulb 23 is a cold cathode tube serving as aluminescent source. In the present embodiment, two fluorescent lightbulbs 23 are included in the fluorescent light bulb assembly 40A. In theglass-tube of the fluorescent light bulb 23, mercury, Ar gas, and Ne gasare contained, and a fluorescent material is applied to the wall of theglass tube.

[0045] Inside each fluorescent light bulb 23, an electrode section 31(not shown in FIG. 5, but shown in FIG. 15) is provided at each end.Wiring 33 (not shown in FIG. 5, but shown in FIG. 10) that is connectedto the electrode section 31 is pulled out.

[0046] Although an electrode section 31 is arranged on each end of thefluorescent light bulb 23, as shown in FIG. 15, the wiring 33 is pulledout only from one side, and connected to a connector 36. Therefore, thewiring 33 includes a short pair of wires that connects the electrodesection 31 nearer to the connector 36, and a long pair of wires thatconnects the other electrode section 31 that is farther from theconnector 36. The long pair of the wires 33 connected to the electrodesection 31 on the far end is pulled out in the same direction as theshort pair of wires 33, running along the backside of the holder 27 asshown in FIG. 6.

[0047] When electricity is applied to the wiring 33, the electrodesection 11 discharges, and mercury gas generates ultraviolet rays, whichhit the fluorescent material, resulting in emission of light. Thefluorescent light bulb 23 further includes a rubber holder 32, providedon the both ends of fluorescent light bulb 23. The holder 27 holds thefluorescent light bulb 23 through the rubber holder 32.

[0048] The holder 27 is made from mainly metal materials such as SUS,steel, and aluminum, and is arranged in the longitudinal direction ofthe fluorescent light bulb 23. A silver vacuum evaporation layer or awhite reflective layer is formed on a face of the holder 27, the facefacing the fluorescent light bulb 23 such that the light from thefluorescent light bulb 23 is reflected efficiently. In this manner, thelight of the fluorescent light bulb 23 is efficiently guided to thelight guide board 24, without diffusing. Further, this holder 27 servesalso as a heat-dissipation component that radiates heat generated by thefluorescent light bulb 23, as described later.

[0049] The rubber holder 32 is made of silicone rubber, for example, inwhich high conductive metal powder is mixed as filler, providing highheat conductivity. The rubber holder 32 is provided at a positioncorresponding to each electrode section 11 of the fluorescent light bulb23. The rubber holder 32 also serves to hold the fluorescent light bulb23 to the holder 27 as mentioned above. Further, the rubber holder 32 isthermally connected to the holder 27 by being attached to the holder 27.

[0050] The light guide board 24 is made of a transparent resin, such asacrylic resin. The light guide board 24 is arranged to face the back ofthe liquid crystal panel 22. Further, as shown in FIG. 6, thefluorescent light bulb 23 is arranged to face the side of the lightguide board 24, i.e., light. injecting side.

[0051] The optical sheet 28 is arranged in the front side of the lightguide board 24 that is, the side that faces the liquid crystal panel 22.The optical sheet 28 condenses and spreads the light emitted from thelight guide board 24, such that the light is efficiently provided to theliquid crystal panel 22. Further, a reflective sheet 30 is arranged onthe backside of the light guide board 24. The reflective sheet 30reflects that portion of the light that leaks from the light guide board24, and returns the leaking light to the interior of the light guideboard 24.

[0052] Next, an explanation follows about a structure of the holder 27that serves as a main part of the present embodiment with reference toFIG. 6. The holder 27 of the present embodiment is characterized byproviding a proximity section 41 at a location in the proximity of thefluorescent light bulb 23 (luminescent source).

[0053] The proximity section 41 is formed by press processing the holder27, and, therefore, can be formed simultaneously with fabrication of theholder 27. For this reason, manufacturing and assembling of thebacklight apparatus 20A do not become complicated even if the proximitysection 41 is formed in the holder 27.

[0054] By the way, the position where temperature rises the most causedby heat generated by the fluorescent light bulbs 23 in the fluorescentlight bulb assembly 40A is where the fluorescent light bulbs 23 faceeach other, i.e., the position where each fluorescent light bulb 23adjoins the other fluorescent light bulbs 23. The present embodimentprovides the proximity section 41 in the holder 27 at the position wherethe temperature rises the most, the proximity section 41 facing thefluorescent light bulbs 23.

[0055] By the structure as described above, the distance between thefluorescent light bulb 23 and the holder 27 becomes small, whichincreases efficiency of heat-dissipation of the heat generated by thefluorescent light bulb 23 through the proximity section 41 and theholder 27. In this manner, the temperature rise of the fluorescent lightbulb 23 is reduced. Especially, as mentioned above, since the proximitysection 41 absorbs the heat of the part where the temperature rises themost due to the heat generated by the fluorescent light bulb 23, andradiates the heat through the holder 27, decrease in brightness of thefluorescent light bulb 23 due to heat is minimized. Further, byperforming heat-dissipation as mentioned above, the temperature rise ofthe light guide board 24 by the fluorescent light bulb 23 is suppressed,which prevents deformation and fusion that may otherwise occur in thelight guide board 24.

[0056] Further, since the heat generated by the fluorescent light bulb23 is dissipated efficiently by the backlight apparatus 20A of thepresent embodiment, high brightness is realized. Therefore, according toLCD 21A using this backlight apparatus 20A, high reliability is realizedwhile a good picture display of high brightness is provided.

[0057] Although the backlight apparatus 20A having two fluorescent lightbulbs 23 is explained above as an example, the present invention canapply to a backlight apparatus having any number of fluorescent lightbulbs 23, the number including 1 and 3.

[0058] Further, although the proximity section 41 is provided nearby amiddle point of the two fluorescent light bulbs 23 in the presentembodiment, when the temperature distribution in a fluorescent lightbulb assembly is known, it is effective to form the proximity section 41near the part where the temperature becomes the highest.

[0059] Next, a second embodiment of the present invention is explained.

[0060]FIG. 7 shows a backlight apparatus 20B, and an LCD 21B using thebacklight apparatus 20B of the second embodiment. Here, in FIG. 7, aboutthe same components as shown in FIG. 5 and FIG. 6 in the firstembodiment, the same reference numbers are attached and the explanationthereof is not repeated. This practice will apply to explanations anddrawings of the third embodiment et seq., to be described later.

[0061] The proximity section 41 of the backlight apparatus 20B of thepresent embodiment is formed in a middle position of the pair offluorescent light bulbs 23, like the first embodiment, where thetemperature becomes the highest in the fluorescent light bulb assembly40B. The second embodiment is characterized by providing the wiring 33of the fluorescent light bulb 23 on a side of the proximity section 41other than the side to which the fluorescent light bulb 23 faces. Thisposition will be hereafter called the backside.

[0062] As described above, the wiring 33, which includes the short pairof wires and the long pair of wires, connected to the electrode sections31 is pulled out to the same direction, with the long pair of wiresrunning on the back side of the holder 27. In the present embodiment,the long pair of wires of the wiring 33 provided on the backside of theholder 27 is arranged in the back position of the proximity section 41.

[0063] Miniaturization of the backlight apparatus 10B is attained bythis configuration. That is, as mentioned above, since the proximitysection 41 is formed close to the high-temperature part of thefluorescent light bulbs 23, a space becomes available in the backsideposition. Compared with a configuration that arranges this wiring 33 inother parts, miniaturization of the backlight apparatus 20B can beattained because the space is available for arranging the long pair ofwires of the wiring 33 that is connected to the electrode section 31.

[0064] Although the proximity section 41 gets heated while dissipatingthe heat generated by the fluorescent light bulbs 23, a heat-resistantmaterial is used as a covering material of the wiring 33. In thismanner, metal lines of the wiring 33 are not exposed by the coveringmaterial melting due to high temperature.

[0065] Next, the third embodiment of the present invention is explained.

[0066]FIG. 8 shows a backlight apparatus 20C, and an LCD 21C using thebacklight apparatus 20C of the third embodiment of the presentinvention.

[0067] The backlight apparatus 20C of the third embodiment includesthree fluorescent light bulbs 23 (designated 23A, 23B, and 23C), inorder to attain high brightness. As shown in FIG. 8, the fluorescentlight bulb 23B is provided in the middle of the three fluorescent lightbulbs 23A, 23B, and 23C. The present embodiment is characterized byhaving arranged the fluorescent light bulb 23B closer to the holder 27than the other fluorescent light bulbs 23A and 23C. Positions of thefluorescent light bulbs 23A, 23B, and 23C can be relatively easilydetermined by arranging supporting holes for the fluorescent light bulbs23A, 23B, and 23C, which are formed on the holder 27.

[0068] By the way, when three or more fluorescent light bulbs areprovided, the fluorescent light bulb located in the middle has the mostintense temperature rise. In the configuration of the present embodimentthat uses the three fluorescent light bulbs 23A, 23B, and 23C, thetemperature of the fluorescent light bulb 23B located in the middlebecomes the highest.

[0069] Accordingly, in the present embodiment, the fluorescent lightbulb 23B is placed near the holder 27. In this manner, the heat of thefluorescent light bulb 23B is better dissipated than other fluorescentlight bulbs 23A and 23C. In this manner, the heat generated by thefluorescent light bulb 23B is efficiently dissipated through the holder27. As the result, the temperature rise of the whole backlight apparatus20C can be suppressed.

[0070] Although a configuration of the fluorescent light bulb assembly40C is described as including the three fluorescent light bulbs 23A,23B, and 23C in the present embodiment, the present invention can beapplied to a fluorescent light bulb assembly having four or morefluorescent light bulbs.

[0071] Next, the fourth embodiment of the present invention isexplained.

[0072]FIG. 9 shows a backlight apparatus 20D, and an LCD 21D using thebacklight apparatus 20D of the fourth embodiment. The present embodimentis characterized by a tapering shape of the space between the holder 27Aand the fluorescent light bulb 23, which are included in the fluorescentlight bulb assembly 40D. The space is the widest at the center of thefluorescent light bulb 23, and decreases in width toward each end(henceforth both end positions) of the fluorescent light bulb 23, wherethe electrode section 31 is formed.

[0073] Specifically, since the diameter size of the fluorescent lightbulb 23 is uniform over its longitudinal direction, the holder 27 isstructured such that the space at the both-end positions is set small(A2 in FIG. 9), while the space at the center is set large (A1 in FIG.9). By employing this structure, the space between the fluorescent lightbulb 23 and holder 27A at the both-end positions is set at a2, and thespace between the fluorescent light bulb 23 and the holder 27A at thecenter is set at a1, where a1>a2.

[0074] According to the structure described above, efficiency of heatdissipation is heightened at the both-end positions, in comparison withthe center. As a result, heat distribution is made relatively uniformover the longitudinal direction of the fluorescent light bulb 23,realizing relatively uniform distribution of brightness of the backlightapparatus 20D.

[0075] Another advantage of the above structure is that inserting intoand removing the fluorescent light bulb assembly 40D from the housing 25is facilitated. That is, in the backlight apparatus 20D of the presentembodiment, the fluorescent light bulb assembly 40D has the smallerdimension a2 at the both ends (namely, both ends of the holder 27A) thanthe center part, and the size of a hole prepared in the housing 25, intowhich the fluorescent light bulb assembly 40D is inserted, is made toaccept the larger dimension a1, which is larger than a2.

[0076] As above, it is easy to insert the smaller end of the fluorescentlight bulb assembly 40D into the insertion hole of the housing 25, whichis made the larger.

[0077] Next, the fifth embodiment of the present invention is explained.

[0078]FIG. 10, FIG. 11, FIG. 12 and FIG. 13 show a backlight apparatus20E, and an LCD 21E using the backlight apparatus 20E of the fifthembodiment.

[0079]FIG. 10 is an exploded and perspective diagram of the LCD 21E ofthe fifth embodiment. As shown in FIG. 10, the LCD 21E of the presentembodiment provides the liquid crystal panel 22 on the backlightapparatus 20E, with the housing 25 provided on the top. Further, thestructure is such that the fluorescent light bulb assembly 40E isinserted into and removed from the backlight apparatus 20E. In addition,a data substrate 34 and a gate substrate 35 are provided on separatesides of the liquid crystal panel 22.

[0080]FIG. 11 is an exploded and perspective diagram expanding andshowing the backlight apparatus 20E.

[0081] The backlight apparatus 20E of the present embodiment includes alight guide board 24, an optical sheet 28, and a reflective sheet 30that are contained in a housing (case) structured by a frame 37 locatedin the upper part, and a bottom metal plate 46 located in the lowerpart. Further, a fluorescent light bulb assembly 40E is also containedin the housing. For this reason, an insertion concavity 38 is formed inthe frame 37, and a guiding concavity 49 is formed in the bottom metalplate 46.

[0082] Furthermore, a bent section 48 is formed in an end section of theguiding concavity 49 of the bottom metal plate 46. The bent section 48is structured as a part of the bottom metal plate 46, forming one body,and is simultaneously formed when the guiding concavity 49 and a sideplate 47 are formed. Here, as a material for the bottom metal plate 46,a metal material with high thermal conductivity is selected.

[0083] Details will be described about an end of the fluorescent lightbulb assembly 40E, the end being the first part inserted into thehousing. The end is the left-hand side end of the fluorescent light bulbassembly 40E in FIG. 11. As shown in FIG. 12, the fluorescent light bulbassembly 40E of the present embodiment includes a fluorescent light bulb23, a holder 27B, and a rubber holder 32A. Here, the structure is suchthat the rubber holder 32A that holds the fluorescent light bulb 23 tothe holder 27B projects from an edge 42 of the holder 27B (toward thebent section 48). The part that projects from the edge 42 of the rubberholder 32A is hereafter called a first projecting section 44.

[0084] On the other side of the fluorescent light bulb assembly 40E,with reference to FIG. 13 (reverse angle), a through hole 43 is formedon the side plate 47 (a part of the bottom metal plate 46), such thatthe through hole 43 faces the side plate 47. A part of a rubber holder32B projects from the through hole 43. The projected part is called asecond projecting section 45.

[0085] In the backlight apparatus 20E that is structured as above, whenthe fluorescent light bulb assembly 40E is inserted to a predeterminedposition in the housing constituted by the frame 37 and the bottom metalplate 46, the first projecting section 44 is thermally connected bycontacting the bent section 48 formed in the bottom metal plate 46.Further, the second projecting section 45 is thermally connected to theside plate 47 of the bottom metal plate 46.

[0086] In this manner, the heat generated by the fluorescent light bulb23 is dissipated by the bottom metal plate 46 through the first and thesecond projecting sections 44 and 45, and by the holder 27B.Specifically, the rubber holder 32A is thermally connected to the bottommetal plate 46, by the first projecting section 44 contacting the bentsection 48 on the left-hand side in FIG. 12. Further, on the other side,the rubber holder 32B is thermally connected to the bottom metal plate46, by the second projecting section 45 contacting the side plate 47.

[0087] As above, the heat generated by the fluorescent light bulb 23 isefficiently dissipated, and the temperature rise of the fluorescentlight bulb 23 can be reduced. Especially, because the first projectingsection 44 and the second projecting section 45 are arranged at bothends of the fluorescent light bulb 23, where the temperature becomes thehighest, the fluorescent light bulb 23 is cooled effectively.

[0088] Furthermore, in the present embodiment, the first projectingsection 44 provided on the left-hand side edge does not slide on, norcontact with, the side plate 47 when the fluorescent light bulb assembly40E is inserted, such that the first projecting section 44 does not wearfrom insertion friction. The second projecting section 45 that is tocontact the side plate 47 is provided in a position where the distanceto slide on the side plate 47 when being inserted is short, such thatwear of the second projecting section 45 by insertion friction isminimized.

[0089] Although the second projecting section 45 and the side plate 47that face each other take a flat shape in the above-mentioned embodimentas shown in FIG. 13, a concavity section 50 may be provided in the sideplate 47 at a predetermined position as shown in FIG. 14, such that thesecond projecting section 45 meets the concavity 50 when the fluorescentlight bulb assembly 40E is installed.

[0090] The concavity 50 is formed such that the second projectingsection 45 is enclosed, as shown by the mark (B) in FIG. 14. In thismanner, the area where the second projecting section 45 contacts theconcavity 50 becomes large, resulting in a higher heat dissipationefficiency, and suppressing temperature rise of the fluorescent lightbulb 23.

[0091] Next, the sixth embodiment of the present invention is explained.

[0092]FIG. 15, FIG. 16 and FIG. 17 show a fluorescent light bulbassembly 40F used in a backlight apparatus and an LCD of the sixthembodiment. The fluorescent light bulb assembly 40F of the presentembodiment is characterized by providing a heat dissipating piece 51between the rubber holder 32 and the light guide board 24, such that theheat dissipating piece 51 is thermally connected with a holder 27C, asshown in FIG. 17.

[0093] In the present embodiment, a structure is such that the heatdissipation component section 51 is provided at an edge of the holder27C in one body, as shown in FIG. 15. Then, the wiring 33 that isbeforehand connected to the fluorescent light bulb 23 and a flange 36 isequipped to the rubber holder 32 that is, in turn, installed in theholder 27C, as shown in FIG. 16. Then, the heat dissipation componentsection 51 is bent and processed in a direction indicated by an arrow,such that the rubber holder 32 is surrounded by the holder 27C and theheat dissipation component section 51. Therefore, when the fluorescentlight bulb assembly 40F is installed in the housing (not shown) of thebacklight apparatus, the heat dissipation component section 51 comesbetween the rubber holder 32 and the light guide board 24.

[0094] Thus, by providing the heat dissipation component section 51 thatis thermally connected with holder 27C between the rubber holder 32 andthe light guide board 24, the heat generated by the fluorescent lightbulb 23 is not conducted from the rubber holder 32 to the light guideboard 24, but is conducted to the holder 27C through the heatdissipation component section 51. In this manner, the light guide board24 is prevented from being damaged by the heat generated by thefluorescent light bulb 23, and a reliable backlight apparatus isrealized.

[0095] As mentioned above, in the present embodiment, since the heatdissipation component section 51 is provided in one body with the holder27C, the number of components does not increase. Further, the one bodystructure of the heat dissipation component section 51 and the holder27C contributes to higher heat conductivity from the heat dissipationcomponent section 51 to the holder 27C.

[0096] Next, the seventh embodiment of the present invention isexplained.

[0097]FIG. 18 and FIG. 19 show a fluorescent light bulb assembly 40Gused in a backlight apparatus and an LCD of the seventh embodiment.

[0098] In the sixth embodiment, the heat dissipation component section51 is formed in one body with the holder 27C. Here, in the seventhembodiment, a clip component 52, as shown in FIG. 18 and which is calleda heat-dissipating clip 52, is employed to help dissipate heat. Theheat-dissipating clip 52 is made of a metal material that has highthermal conductivity and elasticity.

[0099] Accordingly, the heat-dissipating clip 52 is attachable to anddetachable from the holder 27, facilitating assembly and maintenance.

[0100] Next, the eighth embodiment of the present invention isexplained.

[0101]FIG. 20, FIG. 21, FIG. 22, and FIG. 23 show a fluorescent lightbulb assembly 40H used by a backlight apparatus and an LCD of the eighthembodiment.

[0102] The fluorescent light bulb assembly 40H of the present embodimentis structured such that the rubber holder 32C is made of an insulatingmaterial, and an insulator projection 53 is provided to the rubberholder 32C. The insulator projection 53 is formed in one body with therubber holder 32C, and is formed between the electrode section 31 of thefluorescent light bulb 23, and the holder 27, as shown in FIG. 21, FIG.22, and FIG. 23. Further, the insulator projection 53 is formed only ina position facing the holder 27, and is not formed in a position facingthe light guide board 24, as shown in FIG. 20 and FIG. 22.

[0103] Here, the holder 27 is made of a metal material as describedabove, and a large electric current flows through the electrode section31, generating electric discharge. For this reason, a possibility isthat electric discharge may occur between the electrode section 31 andthe holder 27. In order to attain high brightness, a large electriccurrent is required, which increases the possibility of externalelectric discharge occurring. When the external electric dischargeoccurs, metal particles are affixed to the inner wall of the fluorescentlight bulb 23 by sputtering, causing remarkable degradation of thefluorescent light bulb 23, and reliability of the backlight apparatuswill fall.

[0104] In view of this, the present embodiment provides the insulatorprojection 53 to the rubber holder 32C that insulates the electrodesection 31 from the holder 27. In this manner, a route for the electricdischarge to occur becomes long as an arrow shows in FIG. 23, andtherefore, occurrence of the electric discharge is suppressed, enhancingsafety and reliability of the backlight apparatus.

[0105] Further, in the present embodiment, since the insulatorprojection 53 is provided only in an area where the electric dischargemay occur between the electrode section 31 and the holder 27, and wherethe insulator projection 53 faces the holder 27, the light directed tothe light guide board 24 of the fluorescent light bulb 23 is notinterrupted. Therefore, even if the insulator projection 53 is providedin order to prevent the electric discharge from occurring, thebrightness of the backlight apparatus is not lowered.

[0106] According to the present invention, various effects are realizedas follows.

[0107] By providing the proximity section in the holder, dissipationefficiency of the heat generated by the luminous source is improved.

[0108] By providing the space for wiring on the backside of the holder,miniaturization of the backlight apparatus is realized.

[0109] By locating the centrally positioned luminescent source elementsthat tend to be the hottest closer to the holder, temperature rise ofthe luminescent source as the whole is suppressed, resulting inefficient heat dissipation.

[0110] By providing the tapering shape such that the distance betweenthe luminescent source and the holder is the largest at the centralpoint of the luminescent source, and is the smallest at both ends of theluminescent source, relatively uniform heat distribution is attained,and, therefore, relatively uniform brightness of the luminescent sourceis obtained.

[0111] By providing the projecting section to the holder, conductivityof the heat generated by the luminescent source is improved, resultingin enhanced heat dissipation, and suppressing a temperature rise of theluminescent source.

[0112] By providing the concavity shape for the projecting section, thecontacting area is increased, which further improves heat conductivity,resulting in further ability to suppress the temperature rise of theluminescent source.

[0113] By providing the heat dissipation component, dissipation of theheat generated by the luminescent source is enhanced, preventing thelight guide board from being damaged, and realizing a reliable backlightapparatus.

[0114] By providing the heat dissipation component in one body with theholder, the number of components is minimized.

[0115] By providing the heat dissipating clip that is attachable anddetachable, assembly and maintenance is facilitated.

[0116] By providing the insulator projecting section, external electricdischarge between the electrode section of the luminescent source andthe holder is suppressed, enhancing safety and reliability of thebacklight apparatus.

[0117] By providing the insulator projecting section such that the lightfrom the luminescent source is not interrupted, brightness of thebacklight apparatus is not lowered.

[0118] By using the backlight apparatus of the present invention, an LCDthat provides enhanced image quality with high reliability is realized.

[0119] Further, the present invention is not limited to theseembodiments, but various variations and modifications may be madewithout departing from the scope of the present invention.

[0120] The present application is based on Japanese priority applicationNo. 2001-399592 filed on Dec. 28, 2001 with the Japanese Patent Office,the entire contents of which are hereby incorporated by reference.

What is claimed is
 1. A backlight apparatus of an edge light type,comprising: a plurality of luminescent sources, and a holder that isinstalled with the plurality of the luminescent sources, has aheat-dissipating function, and has a proximity section that approachesthe plurality of the luminescent sources.
 2. The backlight apparatus asclaimed in claim 1, wherein wiring of the luminescent source is providedon a side of the proximity section, the side being opposite to anotherside on which the luminescent sources are provided.
 3. A backlightapparatus of an edge light type, comprising: at least three luminescentsources, and a holder that has a heat-dissipating function, and isinstalled with the luminescent sources, wherein one or two luminescentsources that are positioned in a middle of the luminescent sources arepositioned closer to the holder than other luminescent sources.
 4. Abacklight apparatus of an edge light type, comprising: a plurality ofluminescent sources, and a holder that has a heat-dissipating function,and has a tapered part such that a distance between the holder and theluminescent sources decreases toward each longitudinal end of theluminescent sources, with the distance being maximum at the longitudinalcenter position of the luminescent sources.
 5. A backlight apparatus ofan edge light type, comprising: one or more luminescent sources, aholder that is installed with the luminescent sources, a housing that isinstalled with the holder, and a supporting component that holds theluminescent sources in the holder that is installed in the housing, andhas a projecting section that projects outward from the holder such thatthe projecting section is thermally connected to the housing.
 6. Thebacklight apparatus as claimed in claim 5, wherein the projectingsection is projected in a direction in which the holder is inserted intothe housing.
 7. The backlight apparatus as claimed in claim 5, whereinthe projecting section is projected through a hole formed in the holder.8. The backlight apparatus as claimed in claim 5, wherein the housingprovides a concavity section such that the projecting section iscontained in the concavity section.
 9. A backlight apparatus of an edgelight type, comprising: one or more luminescent sources, a light guideboard to which the luminescent sources transmit light, a holder that isinstalled with the luminescent sources, a supporting component thatsupports the luminescent sources in the holder, and a heat-dissipatingcomponent that is thermally connected to the holder, located between thesupporting component and the light guide board.
 10. The backlightapparatus as claimed in claim 9, wherein the heat-dissipating componentis formed in one body with the holder.
 11. The backlight apparatus asclaimed in claim 9, wherein the heat-dissipating component is attachableto and detachable from the holder, having a clip structure.
 12. Abacklight apparatus of an edge light type, comprising: one or moreluminescent sources, a holder that is installed with the luminescentsources, a housing that is installed with the holder, and a supportingcomponent made from an insulating material, having an insulatorprojection section such that the insulator projection section comesbetween an electrode section of the luminescent source and the holder.13. The backlight apparatus as claimed in claim 12, wherein theinsulator projection section is formed only in a position that faces theholder.
 14. A liquid crystal display apparatus, comprising: a liquidcrystal panel, and the backlight apparatus as claimed in claim 9,wherein the luminescent source is provided on a side of a light guideboard.